package top.tagao.features_04_Optional;

import org.junit.jupiter.api.Test;

import java.util.Optional;

/**
 * @author fu-xiao-liu
 * @Date 2022/3/20 19:22
 */
public class OptionalAPi_01 {

    /*
    Optional.of(T t) : 创建一个 Optional 实例，t必须非空；
    Optional.empty() : 创建一个空的 Optional 实例
    Optional.ofNullable(T t)：t可以为null
     */

    //of(T t):保证t是非空的
    @Test
    public void test1(){
        Girl girl = new Girl();
        //girl = null;

        Optional<Girl> optionalGirl = Optional.of(girl);

    }

    //ofNullable(T t)：t可以为null
    @Test
    public void test2(){
        Girl girl = new Girl();
        girl = null;
        Optional<Girl> optionalGirl = Optional.ofNullable(girl);
        System.out.println(optionalGirl);
        //orElse(T t1):如果单前的Optional内部封装的t是非空的，则返回内部的t.
        //如果内部的t是空的，则返回orElse()方法中的参数t1.
        Girl girl1 = optionalGirl.orElse(new Girl("赵丽颖"));
        System.out.println(girl1);

    }

    @Test
    public void test3(){
        Boy boy = null;
        //boy = new Boy();
        //boy = new Boy(new Girl("苍老师"));
        String girlName = getGirlName(boy);
        System.out.println(girlName);
    }

    //使用Optional类的getGirlName():
    public String getGirlName(Boy boy){

        Optional<Boy> boyOptional = Optional.ofNullable(boy);
        //此时的boy1一定非空
        Boy boy1 = boyOptional.orElse(new Boy(new Girl("迪丽热巴")));
        Girl girl = boy1.getGirl();

        Optional<Girl> girlOptional = Optional.ofNullable(girl);
        //girl1一定非空
        Girl girl1 = girlOptional.orElse(new Girl("古力娜扎"));

        return girl1.getName();
    }


}
